Per capita vehicle-miles traveled in the United States dropped by 0.4 percent in 2012, according to the FHWA’s travel trends data released Friday.

Per capita VMT peaked in 2004 and has declined each year since then for a total decline of 7.5 percent (Figure 1). At 9,363, VMT per capita in 2012 reached its lowest level since 1996.

A variety of factors have been cited for the decline, including retiring Baby Boomers; less enthusiasm for cars among Millennials; a move in many places toward more compact and mixed-use development; and demand-side policy efforts, including TDM, tolling and market-pricing of parking. In addition, some trends that fueled VMT growth in the last century have eased: The transition toward women working outside the home is essentially complete, car-ownership has gone from rare to common, and people’s time budgets for car travel may have reached their maximum.

Figure 1. VMT per capita for the United States. Source: FHWA and Census Bureau.

The decline in 2012 was offset by an increase in population, so total VMT was up by 0.3 percent (Figure 2). In the eight-year period of per capita VMT decline, total VMT has declined three years and increased five, for a net decrease of 0.9 percent.

Figure 2. Total VMT (in millions) for the United States. Source: FHWA.

The numbers suggest that, with a stable total VMT, we will still rely on highways for a long time. However, capacity projects that assume increasing VMT may be good places for cash-strapped DOTs to look for savings. And the per capita declines suggest that conventional trip generation assumptions, which drive Transportation Impact Analyses for mitigation and parking requirements, ought to be revisited. SSTI is working on a TIA project and will report out later this year. In the meantime, one source for improved trip generation estimation is Fehr & Peers Mixed Use Trip Generation Model 4.0.